Picea Engelmannii - Subspecies and Hybrids

Subspecies and Hybrids

Two geographical subspecies (treated as varieties by some authors, and as distinct species by others) occur:

• Picea engelmannii subsp. engelmannii (Engelmann spruce). All of the range except as below.
• Picea engelmannii subsp. mexicana (Mexican spruce). Two isolated populations on high mountains in northern Mexico, on the Sierra del Carmen in Coahuila (Sierra Madre Oriental) and on Cerro Mohinora in Chihuahua (Sierra Madre Occidental). Engelmann spruces of the Madrean sky islands mountains in the extreme southeast of Arizona and southwest of New Mexico also probably belong to this subspecies, though this is disputed.

Picea engelmannii, Engelmann spruce, hybridises and intergrades extensively with the closely related white spruce found further north and east in the Rocky Mountains, and to a lesser extent with the closely related Sitka spruce where they meet on the western fringes of the Cascades.